--- You wrote:
Are there reconstructions or theoretical descriptions of Mohe?  Just wondering how old these influence might be in Kitan.
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Hi,
If I'm not mistaken, Shiratori has done some work on Mohe and Suzhen in Saigai minzokushi kenkyu. 
There's a festschrift volume containing some of these reconstructions too.
His reconstruction also discusses the possible genetic affiliations of the language spoken by the Murong Xianbei and Yuwen Xianbei.